During the act of skiing, the leg is subject to numerous forces as a controlled descent of the slope is attempted. In the event of a fall, an uncontrolled situation may occur where the forces generated by skier momentum and other forms of stored energy are applied to the leg in an undesirable way. The most dangerous of these forces comes in the form of twisting and bending moments, which produce the highest probability of injury to the bone and tissue. The application of these moments, generally speaking, cause the bone to "wind-up" or "bend", wherein the amount of twist and/or bend depends on the magnitude and duration of the applied forces and is representative of the amount of energy absorbed by the leg. As in any mechanical system, time is needed for the leg to absorb the energy and to then cause an injury, and, likewise, in the event a release is not realized, time is needed to remove the energy once the applied force is eliminated.
U.S. Pat. No. 3,907,316 relates to a method and device for automatically releasing a ski boot from a ski. Use is made of safety ski bindings in which, when a pressure exceeding a given, possibly adjustable, resistance comes into play, a ski boot holder moves from its locking position to its releasing position, thus releasing the ski boot.
The disclosure of U.S. Pat. No. 3,907,316 proposes a method and device for automatically releasing a ski boot from a ski, in the event of danger. Under the method, force pulses acting on the skier's leg are continuously picked up and compared with a predetermined pulse quantity forming a threshold value. When the threshold value is reached, the connection between the ski and ski boot is released.
If the threshold is not exceeded long enough for the force pulses to apply a dangerous energy level to the leg, the ski binding will not release. Moreover, the bone does not absorb this energy in zero time, and neither does it release the energy in zero time. Thus, there is a need for a method of taking into account the release of energy by the bone to produce a proper release of the ski binding. The present invention fills that need.